1. Technical Field
The present invention relates generally to a braking system for automotive vehicles designed to regulate the braking pressure acting on wheels for optimizing braking conditions, and more particularly to a braking system having a function of returning the brake pressure exerted on wheels back to a driver-operated braking pressure source when decreasing the braking pressure acting on the wheels.
2. Background of Related Art
Braking systems for automotive vehicles are known in the art which regulate the braking pressure supplied to wheel cylinders for optimizing the braking force during braking. In general, such braking systems are classified into a type wherein the braking pressure is returned back to a pressure reservoir when decreasing the braking pressure and a type wherein the brake fluid is recirculated by a pump back to a master cylinder.
The latter type has the advantage over the former type of having no lack of the brake fluid, however, encounters the drawback in that the brake fluid is returned back to the master cylinder each time the pressure of the brake fluid is decreased during depression of a brake pedal by a driver, thereby causing great pressure vibrations to be produced in the master cylinder which are transmitted as a reaction force (generally called kickback), with which the driver feel uncomfortable, against depression of the brake pedal, which may preclude further depression of the brake pedal.